The invention relates to a stator for an eccentric screw pump or an eccentric worm motor having a stator, and includes an outer tube that is provided with a lining of rubber or a rubber-like material and has a hollow space or cavity, in the shape of a double or multiple spiral, for accommodating a rigid rotor that is also in the form of a spiral, whereby the spiral of the stator respectively has one spiral more than does the rotor.
The manner of operation of eccentric screw pumps and eccentric worm motors is also designated as the Moineau principle. From DE 44 03 598 A1 a stator of the aforementioned type is known according to which the lining is fixedly connected with the outer tube, i.e. via chemical bonding between the elastomeric lining and a metallic outer tube. With such a stator there exists the danger that the fixed connection between lining and outer tube becomes detached, primarily if during the operation the stator is subjected to high temperatures and/or chemical stresses.
There are rubber types, such as HNBR, fluoro rubbers, or silicone rubbers, which at temperatures of 160° C. and greater remain functional, yet even with these rubbers the rubber/metal connection can become problematic and can be destroyed during continuous use.
It is an object of the invention to provide a stator that remains functional even under those conditions where the fixed connection between the lining and the outer tube would be destroyed, e.g. by chemical influences or high temperatures.